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26th Annual Symposium on Foundations of Computer Science (sfcs 1985)最新文献

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Design and analysis of dynamic Huffman coding 动态霍夫曼编码的设计与分析
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.18
J. Vitter
{"title":"Design and analysis of dynamic Huffman coding","authors":"J. Vitter","doi":"10.1109/SFCS.1985.18","DOIUrl":"https://doi.org/10.1109/SFCS.1985.18","url":null,"abstract":"We introduce an efficient new algorithm for dynamic Huffman coding, called Algorithm V. It performs one-pass coding and transmission in real-time, and uses at most one more bit per letter than does the standard two-pass Huffman algorithm; this is optimum in the worst case among all one-pass schemes. We also analyze the dynamic Huffman algorithm due to Faller, Gallager, and Knuth. In each algorithm, both the sender and the receiver maintain equivalent dynamically varying Huffman trees. The processing time required to encode and decode a letter whose node in the dynamic Huffman tree is currently on the lth level is O(l); hence, the processing can be done in real time. Empirical tests show that Algorithm V performs quite well in practice, often better than the two-pass method. The proposed algorithm is well-suited for file compression and online encoding/decoding in data networks.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133970323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 39
Parallel tree contraction and its application 平行树收缩及其应用
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.43
G. Miller, J. Reif
{"title":"Parallel tree contraction and its application","authors":"G. Miller, J. Reif","doi":"10.1109/SFCS.1985.43","DOIUrl":"https://doi.org/10.1109/SFCS.1985.43","url":null,"abstract":"Abstract : Trees play a fundamental role in many computations, both for sequential as well as parallel problems. The classic paradigm applied to generate parallel algorithms in the presence of trees has been divide-conquer; finding a 1/3 - 2/3 separator and recursively solving the two subproblems. A now classic example is Brent's work on parallel evaluation of arithmetic expressions. This top-down approach has several complications, one of which is finding the separators. We define dynamic expression evaluation as the task of evaluating the expression with no free preprocessing. If we apply Brent's method, finding the separators seems to add a factor of log n to the running time. We give a bottom-up algorithm to handle trees. That is, all modifications to the tree are done locally. This bottom-up approach which we call CONTRACT has two major advantages over the top-down approach: (1) the control structure is straight forward and easier to implement facilitating new algorithms using fewer processors and less time; and (2) problems for which it was too difficult or too complicated to find polylog parallel algorithms are now easy.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125481388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 407
An optimal parallel algorithm for integer sorting 整数排序的最优并行算法
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.9
J. Reif
{"title":"An optimal parallel algorithm for integer sorting","authors":"J. Reif","doi":"10.1109/SFCS.1985.9","DOIUrl":"https://doi.org/10.1109/SFCS.1985.9","url":null,"abstract":"We assume a parallel RAM model which allows both concurrent writes and concurrent reads of global memory. Our algorithms are randomized: each processor is allowed an independent random number generator. However our stated resource bounds hold for worst case input with overwhelming likelihood as the input size grows. We give a new parallel algorithm for integer sorting where the integer keys are restricted to at most polynomial magnitude. Our algorithm costs only logarithmic time and is the first known where the product of the time and processor bounds are bounded by a linear function of the input size. These simultaneous resource bounds are asymptotically optimal. All previous known parallel sorting algorithms required at least a linear number of processors to achieve logarithmic time bounds, and hence were nonoptimal by at least a logarithmic factor.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125543728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 107
Recognizing circle graphs in polynomial time 在多项式时间内识别圆图
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1145/65950.65951
Csaba P. Gabor, W. Hsu, K. Supowit
{"title":"Recognizing circle graphs in polynomial time","authors":"Csaba P. Gabor, W. Hsu, K. Supowit","doi":"10.1145/65950.65951","DOIUrl":"https://doi.org/10.1145/65950.65951","url":null,"abstract":"Our main result is a polynomialtime algorithm for deciding whether a given graph is a circle graph, that is, the intersection graph of a set of chords on a circle. Our algorithm utilizes two new graph-theoretic results, regarding necessary induced subgraphs of graphs having neither articulation points nor similar pairs of vertices.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124223866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 118
A private interactive test of a boolean predicate a minimum-knowledge public-key cryptosystems 最小知识公钥密码系统中布尔谓词的私有交互测试
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.1
Z. Galil, S. Haber, M. Yung
{"title":"A private interactive test of a boolean predicate a minimum-knowledge public-key cryptosystems","authors":"Z. Galil, S. Haber, M. Yung","doi":"10.1109/SFCS.1985.1","DOIUrl":"https://doi.org/10.1109/SFCS.1985.1","url":null,"abstract":"These properties enable us to define a minimum-knowledge cryptosystem, in which each user receives exactly the knowledge he is supposed to receive and nothing more. In particular, the system is provably secure against both chosen-message and chosen-ciphertext attack. ~1oreover, extending the Diffie-Hellman mo<tel, it allows a user to encode messages to other users with his own public key. This enables a symmetrIc use of public-key encryption.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129247044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 66
Fast parallel computation with permutation groups 基于置换群的快速并行计算
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.26
E. Luks, P. McKenzie
{"title":"Fast parallel computation with permutation groups","authors":"E. Luks, P. McKenzie","doi":"10.1109/SFCS.1985.26","DOIUrl":"https://doi.org/10.1109/SFCS.1985.26","url":null,"abstract":"We develop fast parallel solutions to a number of basic problems involving solvable and nilpotent permutation groups. Testing solvability is in NC, and RNC includes, for solvable groups, finding order, testing membership, finding the derived series and finding a composition series. Additionally, for nilpotent groups, one can, in RNC, find the center, a central composition series, and point-wise stabilizers of sets. There are applications to graph isomorphism. In fact, we exhibit a class of vertex-colored graphs for which determining isomorphism is NC-equivalent to computing ranks of matrices Over small fields. A useful tool is the observation that the problem of finding the smallest subspace containing a given set of vectors and closed under a given set of linear transformations (all over a small field) belongs to RNC.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123122211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Average case lower bounds on the construction and searching of partial orders 构造和搜索偏序的平均下界
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.13
Harry G. Mairson
{"title":"Average case lower bounds on the construction and searching of partial orders","authors":"Harry G. Mairson","doi":"10.1109/SFCS.1985.13","DOIUrl":"https://doi.org/10.1109/SFCS.1985.13","url":null,"abstract":"It is very well known in computer science that partially ordered files are easier to search. In the worst case, for example, a totally unordered file requires no preprocessing, but ¿(n) time to search, while a totally ordered file requires ¿(n log n) preprocessing time to sort, but can be searched in O(log n) time. Behind the casual observation, then, lurks the notion of a computational tradeoff between sorting and searching. We analyze this tradeoff in the average case, using the decision tree model. Let P be a preprocessing algorithm that produces partial orders given a set U of n elements, and let S be a searching algorithm for these partial orders. Assuming any of the n! permutations of the elements of U are equally likely, and that we search for any y isin; U with equal probability (in unsuccessful search, all \"gaps\" are considered equally likely), the average costs P(n) of preprocessing and S(n) of searching may be computed. We demonstrate a tradeoff of the form P(n) + n log S(n) = ¿(n log n), for both successful and unsuccessful search. The bound is tight up to a constant factor. In proving this tradeoff, we show a lower bound on the average case of searching a partial order. Let A be a partial order on n elements consistent with Π permutations. We show S(n) = ¿(Π3/n/n2) for successful search of A, and S(n) = ¿(Π2/n/n) for unsuccessful search. These lower bounds show, for example, that heaps require linear time to search on the average.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115712884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Distributed BFS algorithms 分布式BFS算法
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.20
B. Awerbuch, R. Gallager
{"title":"Distributed BFS algorithms","authors":"B. Awerbuch, R. Gallager","doi":"10.1109/SFCS.1985.20","DOIUrl":"https://doi.org/10.1109/SFCS.1985.20","url":null,"abstract":"This paper develops a new distributed BFS algorithm for an asynchronous communication network. This paper presents two new BFS algorithms with improved communication complexity. The first algorithm has complexity O((E+V1.5)¿logV) in communication and O(V1.5¿logV) in time. The second algorithm uses the technique of the first recursively and achieves O(E¿2 √logVloglogV) in communication and O(V¿2√logVloglogV) in time.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123280888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 54
Why certain subgraph computations requite only linear time 为什么某些子图计算只需要线性时间
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.66
M. Bern, E. Lawler, A. Wong
{"title":"Why certain subgraph computations requite only linear time","authors":"M. Bern, E. Lawler, A. Wong","doi":"10.1109/SFCS.1985.66","DOIUrl":"https://doi.org/10.1109/SFCS.1985.66","url":null,"abstract":"A general problem in computational graph theory is that of finding an optimal subgraph H of a given weighted graph G. The matching problem (which is easy) and the traveling salesman problem (which is not) are well known examples of this general problem. In the literature one can also find a variety of ad hoc algorithms for solving certain special cases in linear time. We present a general methodology for constructing linear time algorithms in the case that the graph G is defined by certain rules of composition (as are trees, series parallel graphs, and outerplanar graphs) and the desired subgraph H satisfies a \"regular\" property (such as independence or matching). This methodology is applied to obtain a linear time algorithm for computing the irredundance number of a tree, a problem for which no polynomial time algorithm was previously known.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125547143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 29
Random polynomial time is equal to slightly-random polynomial time 随机多项式时间等于稍微随机多项式时间
26th Annual Symposium on Foundations of Computer Science (sfcs 1985) Pub Date : 1985-10-21 DOI: 10.1109/SFCS.1985.45
U. Vazirani, V. Vazirani
{"title":"Random polynomial time is equal to slightly-random polynomial time","authors":"U. Vazirani, V. Vazirani","doi":"10.1109/SFCS.1985.45","DOIUrl":"https://doi.org/10.1109/SFCS.1985.45","url":null,"abstract":"Random Polynomial Time (Rp) is currently considered to be the class of tractable computational problems. Here one assumes a source of truly random bits. However, the known sources of randomness are imperfect. They can be modeled as an adversary source, called slightly-random source. Slightlyrandom Polynomial Time (SRp) is the class of problems solvable in polynomial time using such a source. SRp is thus a more realistic definition of a tractable computational problem. In this paper we give an affirmative answer to the question \"is Rp = SRp?\" Our proof method is constructive: given an Rp algorithm for a problem, we show how to obtain an SRp algorithm for it. Studying the relationship between randomized and deterministic computation is currently an important issue. A central question here is \"is Rp = P?\" Our result may be a step towards answering this question.","PeriodicalId":296739,"journal":{"name":"26th Annual Symposium on Foundations of Computer Science (sfcs 1985)","volume":"2 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126326748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 101
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